Watts to Gigawatts (W to GW)

1 watt equals 1×10⁻⁹ gigawatts exactly.

How to convert watts to gigawatts

To convert watts to gigawatts, multiply the number of watts by 1×10⁻⁹. This factor is exact. To go the other way, multiply gigawatts by 1,000,000,000.

gigawatts = watts × 1×10⁻⁹

Example: 10 watts = 1×10⁻⁸ gigawatts.

Several different horsepower units exist. This site lists mechanical (745.7 W), metric (735.5 W) and electrical (746 W) horsepower separately.

About these units

Watt (W)

Metric (SI)Current unit

The SI unit of power: one joule per second. A typical LED bulb uses 5–10 W and a laptop 30–60 W.

Credit for the name goes to C. William Siemens, who proposed it in August 1882 in his presidential address to the British Association for the Advancement of Science. He chose it to honor James Watt, the Scottish inventor who in 1776 improved the Newcomen steam engine. An International Conference on Electric Units and Standards adopted Siemens' definition in London in October 1908 as the international watt. After the 1948 General Conference on Weights and Measures the unit was redefined in absolute terms, and in 1960 the 11th General Conference adopted it into the SI as the unit of power.

Today one watt is one joule per second, or equivalently one volt times one ampere. Orders-of-magnitude tables put an LED light bulb at about 7 W and an adult's basal metabolic rate at roughly 100 W. A 100 kg person climbing a 3 m ladder in 5 seconds works at about 600 W, while a laborer can sustain around 75 W over an eight-hour day. The watt measures a rate, so it says how fast energy is being used, not how much has been used in total.

The watt is the reference unit for power on this site.

Sources: Wikipedia: Watt; Wikipedia: Orders of magnitude (power)

Gigawatt (GW)

Metric (SI)Current unit

One billion watts. The scale of large power plants and national grids.

At a billion watts, power stops being a property of a single machine and becomes a property of a power system. A gigawatt is roughly the annually averaged power consumption of a city of 1.8 million inhabitants, and it is used for large power plants, national grids and, increasingly, large data centers. Planners talk in gigawatts because a country's demand, or the capacity of a new wind or solar program, is far too big to quote sensibly in kilowatts.

Some real installations show the scale. The largest unit of Belgium's Doel nuclear station has a peak output of 1.04 GW, some HVDC converters have been built with ratings up to 2 GW, and China's Three Gorges Dam is rated at roughly 22 GW. Germany's installed wind capacity was 25.8 GW in 2010. One common slip is writing gigawatts per hour, which is a rate of change used for grid ramping, when gigawatt-hours, a quantity of energy, is meant.

1 gigawatt = 1,000,000,000 watts (exactly).

Sources: Wikipedia: Gigawatt; Wikipedia: Orders of magnitude (power)

Related conversions

See all power units.